1. Field of the Invention
This invention relates broadly to the analysis of two phase fluid flow.
2. Description of Related Art
There are many petroleum bearing formations from which oil cannot be recovered by conventional means because the oil is so viscous that it will not flow from the formation to a conventional oil well. Examples of such formations are the bitumen deposits in Canada and the United States and the heavy oil deposits in Canada, the United States, and Venezuela. In these deposits, the oil is so viscous under the temperatures and pressures prevailing within the formations that it flows very slowly (or not at all) in response to the force of gravity. Heavy oil is an asphaltic, dense (low API gravity), and viscous oil that is chemically characterized by its contents of asphaltenes. Most heavy oil is found at the margins of geological basins and is thought to be the residue of formerly light oil that has lost its light molecular weight components through degradation by bacteria, water-washing, and evaporation.
Heavy oil is typically recovered by injecting superheated steam into an oil reservoir, which reduces the oil's viscosity and increases the reservoir pressure through displacement and partial distillation of the oil. Steam may be injected continuously utilizing separate injection and production wells. Alternatively, the steam may be injected in cycles such that the well is used alternatively for injection and production (a “huff and puff” process).
A large percentage of heavy oil recovery methods use steam injection with different well arrangements, but fail to provide adequate support for monitoring the fluid flow into and through the injector well for control and optimization of the injection process.